<!DOCTYPE html>
<html>
	<head>
			<meta charset="utf-8">
			<title></title>
		</head>
		<body>
			<input type="text" id="input1" />
			+
			<input type="text" id="input2" />
			
			<input type="button" value="=" onclick="add()"/>
			<span id="resultSpan"></span>
			
			<script type="text/javascript">
				
				// parseInt()  将字符串转换为number整数
				// parseFloat() 将字符串转换为number浮点数
				
				function add()
				{
					// input1 输元素
					var input1 = document.getElementById("input1");
					var num1 = parseInt(input1.value);
					var input2 = document.getElementById("input2");
					var num2 = parseInt(input2.value);
					var num3 = num1+num2;
					var resultSpan = document.getElementById("resultSpan");
					resultSpan.innerHTML = num3;
				}
			</script>
			
		</body>
</html>
